x86/cpu/vmware: Use the full form of INL in VMWARE_PORT

LLVM's assembler doesn't accept the short form INL instruction:

  inl (%%dx)

but instead insists on the output register to be explicitly specified:

  <inline asm>:1:7: error: invalid operand for instruction
          inl (%dx)
             ^
  LLVM ERROR: Error parsing inline asm

Use the full form of the instruction to fix the build.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Thomas Hellstrom <thellstrom@vmware.com>
Cc: clang-built-linux@googlegroups.com
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: virtualization@lists.linux-foundation.org
Cc: "VMware, Inc." <pv-drivers@vmware.com>
Cc: x86-ml <x86@kernel.org>
Link: https://github.com/ClangBuiltLinux/linux/issues/734
Link: https://lkml.kernel.org/r/20191007192129.104336-1-samitolvanen@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index 9735139..46d7326 100644 (file)
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -49,7 +49,7 @@
 #define VMWARE_CMD_VCPU_RESERVED 31
 
 #define VMWARE_PORT(cmd, eax, ebx, ecx, edx)                           \
-       __asm__("inl (%%dx)" :                                          \
+       __asm__("inl (%%dx), %%eax" :                                   \
                "=a"(eax), "=c"(ecx), "=d"(edx), "=b"(ebx) :            \
                "a"(VMWARE_HYPERVISOR_MAGIC),                           \
                "c"(VMWARE_CMD_##cmd),                                  \